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Add caching to DrawShapedText #3033

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Add caching to DrawShapedText #3033

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cd12eef
add caching to DrawShapedText
MichaelRumpler Oct 8, 2024
e74a183
use a Dictionary instead of a ConcurrentDictionary for the cache
MichaelRumpler Nov 6, 2024
7842f57
add the missing lock in ClearCache()
MichaelRumpler Nov 11, 2024
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181 changes: 181 additions & 0 deletions binding/Binding.Shared/HashCode.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -145,5 +145,186 @@ public int ToHashCode ()
hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1> (T1 value1)
{
// Provide a way of diffusing bits from something with a limited
// input hash space. For example, many enums only have a few
// possible hashes, only using the bottom few bits of the code. Some
// collections are built on the assumption that hashes are spread
// over a larger space, so diffusing the bits may help the
// collection work more efficiently.

uint hc1 = (uint)(value1?.GetHashCode () ?? 0);

uint hash = MixEmptyState ();
hash += 4;

hash = QueueRound (hash, hc1);

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2> (T1 value1, T2 value2)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);

uint hash = MixEmptyState ();
hash += 8;

hash = QueueRound (hash, hc1);
hash = QueueRound (hash, hc2);

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2, T3> (T1 value1, T2 value2, T3 value3)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);
uint hc3 = (uint)(value3?.GetHashCode () ?? 0);

uint hash = MixEmptyState ();
hash += 12;

hash = QueueRound (hash, hc1);
hash = QueueRound (hash, hc2);
hash = QueueRound (hash, hc3);

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2, T3, T4> (T1 value1, T2 value2, T3 value3, T4 value4)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);
uint hc3 = (uint)(value3?.GetHashCode () ?? 0);
uint hc4 = (uint)(value4?.GetHashCode () ?? 0);

Initialize (out uint v1, out uint v2, out uint v3, out uint v4);

v1 = Round (v1, hc1);
v2 = Round (v2, hc2);
v3 = Round (v3, hc3);
v4 = Round (v4, hc4);

uint hash = MixState (v1, v2, v3, v4);
hash += 16;

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2, T3, T4, T5> (T1 value1, T2 value2, T3 value3, T4 value4, T5 value5)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);
uint hc3 = (uint)(value3?.GetHashCode () ?? 0);
uint hc4 = (uint)(value4?.GetHashCode () ?? 0);
uint hc5 = (uint)(value5?.GetHashCode () ?? 0);

Initialize (out uint v1, out uint v2, out uint v3, out uint v4);

v1 = Round (v1, hc1);
v2 = Round (v2, hc2);
v3 = Round (v3, hc3);
v4 = Round (v4, hc4);

uint hash = MixState (v1, v2, v3, v4);
hash += 20;

hash = QueueRound (hash, hc5);

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2, T3, T4, T5, T6> (T1 value1, T2 value2, T3 value3, T4 value4, T5 value5, T6 value6)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);
uint hc3 = (uint)(value3?.GetHashCode () ?? 0);
uint hc4 = (uint)(value4?.GetHashCode () ?? 0);
uint hc5 = (uint)(value5?.GetHashCode () ?? 0);
uint hc6 = (uint)(value6?.GetHashCode () ?? 0);

Initialize (out uint v1, out uint v2, out uint v3, out uint v4);

v1 = Round (v1, hc1);
v2 = Round (v2, hc2);
v3 = Round (v3, hc3);
v4 = Round (v4, hc4);

uint hash = MixState (v1, v2, v3, v4);
hash += 24;

hash = QueueRound (hash, hc5);
hash = QueueRound (hash, hc6);

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2, T3, T4, T5, T6, T7> (T1 value1, T2 value2, T3 value3, T4 value4, T5 value5, T6 value6, T7 value7)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);
uint hc3 = (uint)(value3?.GetHashCode () ?? 0);
uint hc4 = (uint)(value4?.GetHashCode () ?? 0);
uint hc5 = (uint)(value5?.GetHashCode () ?? 0);
uint hc6 = (uint)(value6?.GetHashCode () ?? 0);
uint hc7 = (uint)(value7?.GetHashCode () ?? 0);

Initialize (out uint v1, out uint v2, out uint v3, out uint v4);

v1 = Round (v1, hc1);
v2 = Round (v2, hc2);
v3 = Round (v3, hc3);
v4 = Round (v4, hc4);

uint hash = MixState (v1, v2, v3, v4);
hash += 28;

hash = QueueRound (hash, hc5);
hash = QueueRound (hash, hc6);
hash = QueueRound (hash, hc7);

hash = MixFinal (hash);
return (int)hash;
}

public static int Combine<T1, T2, T3, T4, T5, T6, T7, T8> (T1 value1, T2 value2, T3 value3, T4 value4, T5 value5, T6 value6, T7 value7, T8 value8)
{
uint hc1 = (uint)(value1?.GetHashCode () ?? 0);
uint hc2 = (uint)(value2?.GetHashCode () ?? 0);
uint hc3 = (uint)(value3?.GetHashCode () ?? 0);
uint hc4 = (uint)(value4?.GetHashCode () ?? 0);
uint hc5 = (uint)(value5?.GetHashCode () ?? 0);
uint hc6 = (uint)(value6?.GetHashCode () ?? 0);
uint hc7 = (uint)(value7?.GetHashCode () ?? 0);
uint hc8 = (uint)(value8?.GetHashCode () ?? 0);

Initialize (out uint v1, out uint v2, out uint v3, out uint v4);

v1 = Round (v1, hc1);
v2 = Round (v2, hc2);
v3 = Round (v3, hc3);
v4 = Round (v4, hc4);

v1 = Round (v1, hc5);
v2 = Round (v2, hc6);
v3 = Round (v3, hc7);
v4 = Round (v4, hc8);

uint hash = MixState (v1, v2, v3, v4);
hash += 32;

hash = MixFinal (hash);
return (int)hash;
}
}
}
93 changes: 90 additions & 3 deletions source/SkiaSharp.HarfBuzz/SkiaSharp.HarfBuzz/CanvasExtensions.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,7 @@
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;

namespace SkiaSharp.HarfBuzz
{
Expand Down Expand Up @@ -30,8 +33,10 @@ public static void DrawShapedText(this SKCanvas canvas, string text, float x, fl
if (string.IsNullOrEmpty(text))
return;

using var shaper = new SKShaper(font.Typeface);
var shaper = GetShaper(font.Typeface);
canvas.DrawShapedText(shaper, text, x, y, textAlign, font, paint);
if (cacheDuration == 0)
shaper.Dispose();
}

[Obsolete("Use DrawShapedText(SKShaper shaper, string text, SKPoint p, SKTextAlign textAlign, SKFont font, SKPaint paint) instead.")]
Expand Down Expand Up @@ -70,7 +75,7 @@ public static void DrawShapedText(this SKCanvas canvas, SKShaper shaper, string
font.Typeface = shaper.Typeface;

// shape the text
var result = shaper.Shape(text, x, y, font);
var result = GetShapeResult(shaper, text, font);

// create the text blob
using var builder = new SKTextBlobBuilder();
Expand Down Expand Up @@ -99,7 +104,89 @@ public static void DrawShapedText(this SKCanvas canvas, SKShaper shaper, string
}

// draw the text
canvas.DrawText(textBlob, xOffset, 0, paint);
canvas.DrawText(textBlob, x + xOffset, y, paint);

if (clearCacheTimer is null && cacheDuration > 0)
clearCacheTimer = new Timer(_ => ClearCache(), null, 0, cacheDuration);
}

private static uint cacheDuration = 0;

public static void SetShaperCacheDuration(this SKCanvas canvas, uint milliseconds) => SetShaperCacheDuration(milliseconds);
public static void SetShaperCacheDuration(uint milliseconds)
{
cacheDuration = milliseconds;

clearCacheTimer?.Change(0, cacheDuration);
}

private static readonly Dictionary<int, (SKShaper shaper, DateTime cachedAt)> shaperCache = new();
private static readonly Dictionary<int, (SKShaper.Result shapeResult, DateTime cachedAt)> shapeResultCache = new();

private static SKShaper GetShaper(SKTypeface typeface)
{
if (cacheDuration == 0)
return new SKShaper(typeface);

var key = HashCode.Combine(typeface.FamilyName, typeface.IsBold, typeface.IsItalic);

SKShaper shaper;
lock (shaperCache)
{
shaper = shaperCache.TryGetValue(key, out var value)
? value.shaper
: new SKShaper(typeface);

shaperCache[key] = (shaper, DateTime.Now); // update timestamp
Comment on lines +136 to +140
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Can this not be done in a single step using GetOrAdd?

https://learn.microsoft.com/dotnet/api/system.collections.concurrent.concurrentdictionary-2.getoradd?view=net-8.0#system-collections-concurrent-concurrentdictionary-2-getoradd(-0-system-func((-0-1)))

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I don't know how GetOrAdd could help, but I tried AddOrUpdate here:

var newTuple = shaperCache.AddOrUpdate(key,
	_ => (new SKShaper(typeface), DateTime.Now),
	(_, old) => (old.shaper, DateTime.Now));

But the simple Dictionary with a lock is still faster.

lock (shaperCache)
{
	shaper = shaperCache.TryGetValue(key, out var value)
		? value.shaper
		: new SKShaper(typeface);

	shaperCache[key] = (shaper, DateTime.Now);      // update timestamp
}

}
return shaper;
}

private static SKShaper.Result GetShapeResult(SKShaper shaper, string text, SKFont font)
{
if (cacheDuration == 0)
return shaper.Shape(text, 0, 0, font);

var key = HashCode.Combine(font.Typeface.FamilyName, font.Size, font.Typeface.IsBold, font.Typeface.IsItalic, text);

SKShaper.Result result;
lock (shapeResultCache)
{
result = shapeResultCache.TryGetValue(key, out var value)
? value.shapeResult
: shaper.Shape(text, 0, 0, font);

shapeResultCache[key] = (result, DateTime.Now); // update timestamp
}
return result;
}

private static Timer clearCacheTimer = null;

private static void ClearCache()
{
var outdated = DateTime.Now - TimeSpan.FromMilliseconds(cacheDuration);

foreach (var kv in shaperCache.AsEnumerable())
{
if (kv.Value.cachedAt < outdated)
{
if (shaperCache.Remove(kv.Key))
kv.Value.shaper.Dispose();
}
}

foreach (var kv in shapeResultCache.AsEnumerable())
{
if (kv.Value.cachedAt < outdated)
shapeResultCache.Remove(kv.Key);
}

if ((shaperCache.Count == 0 && shapeResultCache.Count == 0) || cacheDuration == 0)
{
clearCacheTimer?.Dispose();
clearCacheTimer = null;
}
}
}
}
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